Minimal Supergravity Models of Inflation

TL;DR

This paper introduces a supergravity framework with a flexible inflaton potential, enabling single-field inflation models that match desired cosmological parameters without extra scalar stabilization issues.

Contribution

It develops a superconformal master action for supergravity models with an arbitrary function, allowing for versatile inflationary potentials and matching observational data.

Findings

Models can describe any inflaton potential vanishing at the minimum.

Inflationary parameters n_s and r can be freely fitted.

Extra scalars do not need stabilization during inflation.

Abstract

We present a superconformal master action for a class of supergravity models with one arbitrary function defining the Jordan frame. It leads to a gauge-invariant action for a real vector multiplet, which upon gauge fixing describes a massive vector multiplet, or to a dual formulation with a linear multiplet and a massive tensor field. In both cases the models have one real scalar, the inflaton, naturally suited for single-field inflation. Vectors and tensors required by supersymmetry to complement a single real scalar do not acquire vev's during inflation, so there is no need to stabilize the extra scalars which are always present in the theories with chiral matter multiplets. The new class of models can describe any inflaton potential which vanishes at its minimum and grows monotonically away from the minimum. In this class of supergravity models one can fit any desirable choice of inflationary parameters n_s and r.